Spark plug testing and setting apparatus



1959 G. s. CARBONNEAU 2,899,634

SPARK PLUG TESTING AND SETTING APPARATUS Filed Sept. 17, 1956 T T. 5. :j

INVENTOR. l 60/700/16195650/7/11770 2,899,634 Patented Aug. 11, 1959 SPARK PLUG TESTING AND SETTING APPARATUS Gordon S. Carbonneau, Grand Rapids, Application September 17, 1956, Serial No. 610,065

Claims. (Cl. 324-) This invention relates to improvements in spark plug testing and setting apparatus. The principle objects of this invention are:

First, to provide apparatus that will accurately test and adjust a set of spark plugs so thatthey will all spark under the same potential and operating conditions.

Second, to provide spark plug testing apparatus that will take into account and compensate for different surface conditions on the sparking points of spark plugs.

Third, to improve the operating characteristics of automotive engines by providing means for adjusting the spark plugs of the engine so they will all fire at the same potential in the engine.

Other objects and advantages of the invention will be apparent from a consideration of the following description and claims. The drawings, of which there is one sheet, illustrate a highly practical form of the testing and adjusting apparatus and two possible arrangements thereof.

Fig. 1 is a top plan view, partially broken away in cross section, of the plug testing chamber with sources of electrical energy and gas pressure conventionally illustrated and operatively connected to the chamber.

Fig. 2 is a view conventionally illustrating one possible arrangement of the test apparatus.

Fig. 3 is a view conventionally illustrating another pos sible arrangement of the apparatus. v

It is well known in the automotive industry that the time of firing or sparking'of the spark plugs of an engine is very critical to smooth operation of an engine and ignition engineers expend great amounts of time, money and energy to insure that the electrical system will build up and deliver a certain sparking potential at definite fractional seconds of time in the cycle of any particular engine. This potential is then delivered to a set of similar spark plugs and while it is recognized that the spark gap setting of the plugs will affect the timing and operation of the engine testing and adjustment of the spark plugs has been left to a rough scraping of carbon and the compressor 9. A pressure indicating gage 10 having an escape valve 11 is connected to the outlet opening 7.

One side of the block 1 is provided with a series of threaded openings 12 into the chamber 2 adapted to receive the threaded ends of a set of spark plugs 13. The

opposite side of the block is provided with a series of shouldered holes 14 opening to the chamber in opposition to the openings 12 and threaded at their outer ends as at 15. Packing nuts 16 are threaded into the threads 15 around gap adjusting pins 17 that extend slidably through the holes 14. Gaskets 18 are clamped by the nuts 16 against the shoulders of the holes and around the pins to seal the pins in the chamber. The pins 17 are threaded in the packing nuts as at 19 for axial adjustment into gap closing engagement with the outer grounded points 20 of the spark plugs in the openings 12. The pins 17 have finger pieces 21 on their outer ends for easy adjustment and are desirably but not necessarily made of electrically insulating material such as plastic.

The electrical system associated with the test block includes a source of regulatable high voltage 22 connected through a switch 23 to the block 1 at 24 thus forming a ground or return from the shells 25 of the spark plugs. A plurality of lead wires 26 from the power source have terminal caps 27 adapted to be connected to the insulated terminals 28 of the spark plugs. The terminals 28 connect to the center points 29 of the plugs as is well known. It will be understood that a spark plug or a dummy plug fill each of the holes 12 when the apparatus is in use.

Figures 2 and 3 illustrate possible different ways of connecting the electrical system. In Fig. 2 the secondary coil 30 and adjustable resistor 31 of the power source connect to the block 1 and a rotary selector switch 32 for individually testing each spark plug. The switch 32 may be manually adjusted or motor operated as an automotive distributor to rapidly and successively fire all the plugs. The primary coil 33 and battery 34 that charge the secondary coil are connected through the, switch 35 that can be manually operated or automatically operated as by a vibrator. The conventional illustration in Figs. 2 and 3 contemplates the incorporation of the pressure gage and exhaust valve of the system into the pressure regulating valve 8.

In Fig. 3 the secondary coil 30 is connected in parallel to all of the lead wires 26 to simultaneously charge all the plugs 13. Those plugsthat are properly adjusted will then fire all at once. i

To operate the apparatus the gaps of a set of plugs are widened beyond proper gap settings and the plugs are installed in the block. Pressure in the chamber 2 is adjusted by the regulating valve 8 and gage 10 to a high pressure comparableto the compression pressure of the residue off of the points and an only roughly accurate mechanical spacing of the points. I have found that many conditions other than gap space such as surface condi-' tion and contour will affect the potential at which a spark plug will fire or spark. Thus plugs of the same gap setting will fire at different times in the time build up of the spark voltage and keep the engine from operating as smoothly as possible.

In order that all the spark plugs of any given. engine can be adjusted to spark at the same potential, my apparatus provides an elongated bar of metal 1, having a rectangular recess or chamber 2 cut therein. The chamber is closed by a transparent plate 3 having a clamping plate 4 around its edges that is sealingly clamped to the block by screws 5. An inlet opening 6 is formed in one end of the block and an outlet opening 7 in the other. A pressure regulating valve illustrated conventionally at 8 is connected to the chamber 2 through the inlet open Sand pins 17 are successively advanced to close the spark plug gaps until each pl'ug' fires at the test voltage and pressure. Thus while the mechanical gap spacing of the plugs may not be the same, all the plugs of thes'et are identically gapped electrically and all will fire at the same I point in the ignition cycle of the engine in which they ing to deliver air under pressure from a source such as 7 are installed.

Various other arrangments and connections of the parts of the apparatus may be devised that will fall within the scope of the invention as defined by the claims.

Having thus described the invention what is claimed as new and is desired to be secured by Letters Patent is:

1. Spark plug testing and setting apparatus comprising an elongated metal bar member having an elongated cavity formed therein, a transparent pressure resistant plate secured over said cavity and sealed around the edges thereof, an inlet formed in one end of said member to said cavity, a source of regulatable gaseous pressure connected to said cavity through said inlet, an outlet from said cavity formed in the other end of said member, a pressure gage and outlet valve connected to said cavity through said outlet a plurality of threaded holes formed through a side wall of said member into said cavity and adapted to receive a plurality of spark plugs, other holes formed through another wall of said member into-said cavity and opposed to said first holes, a plurality of elec trically insulating gap adjusting rods extending slidably through said other holes in opposed relation to the bottom points of spark plugs in said first holes, means sealing said cavity wall around said rods, thread means for axially adjusting said rods into gap closing engagement with said points, and a source of adjustable high voltage connected on one side to the shells of said plugs through said metal bar and adapted to be connected on the other side to the insulated center terminals of the plugs in said member.

2. Spark plug testing and setting apparatus comprising an elongated member having an elongated cavity formed therein, a transparent pressure resistant plate secured over said cavity and sealed around the edges thereof, an inlet formed in said member to said cavity, a source of regulatable gaseous pressure connected to said cavity through said inlet, an outlet from said cavity formed in said member, a pressure gage and'outlet valve connected to said cavity through said outlet, a plurality of threaded holes formed through a side wall of said member into said cavity and adapted to receive a plurality of spark plugs, other'holes formed through another wall of said member into said cavity and opposed to said first holes, a plurality of gap adjusting rods extending slidably through said other holes in opposed relation to the bottom points of spark plugs in said first holes, means sealing said cavity wall around said rods, thread means for axially adjusting said rods into gap closing engagement with said points, and a source of high voltage connected on one side to the shells of said plugs and adapted to be connected on the other side to the insulated center terminals of the plugs in said member.

3. Spark plug testing and setting apparatus comprising means forming an elongated cavity, a transparent pressure resistant plate secured over said cavity and sealed around the edges thereof, a source of regulatable gaseous pressure connected to said cavity, a pressure gage and outlet valve connected to said cavity, a plurality of threaded holes formed through a side wall of said cavity and adapted to receive a plurality of spark plugs, other holes formed through another wall of said cavity and opposed to said first holes, a plurality of gap adjusting rods extending slidably through said other holes in opposed'relation to the bottom points of spark plugs in said first holes, means sealing said cavity walls around said rods, thread means for axially adjusting said rods into gap closing engagement with said points, and a source of regulatable high voltage connected on one side to the shells of said plugs and adapted to be connected on the other side to the insulated center terminals of the plugs in said cavity.

4. Spark plug testing and setting apparatus comprising means forming an elongated cavity, a transparent pres sure resistant plate secured over said cavity and sealed around the edges thereof, asource of regulatable gaseous pressure connected to said cavity, a plurality of threaded holes formed through a side wall of said cavity and adapted to receive a plurality of spark plugs, other holes.

formed through another wall of said cavity and opposed to said firstholes, a plurality of gap adjusting rods extending slidably through said other holes in opposed relation to the bottom points of spark plugs in said first holes, means sealing said cavity wall around said rods,

4 connected on one side to the shells of said plugs and adapted to be connected on the other side to the insulated center treminals of the plugs iri'said cavity.

5. Spark plug testing and setting apparatus comprising means forming a cavity, a transparent pressure resistant plate secured over said cavity and sealed around the edges thereof, a source ofgaseous pressure connected to said cavity, a plurality of threaded holes formed through a wall of said cavity and adapted to receive a plurality of spark plugs, other holes formed through a wall of said cavity and opposed to said first holes, a plurality of gap adjusting rods extending slidably through said other holes in opposed relation to the bottom points of spark 'plugs in said first holes, means sealing said cavity wall around said rods, means for axially adjusting said rods into gap closing engagement with said points, and a source of high voltage connected on one side to the shells of said plugs and adapted to be connected on the other side to the insulated center terminals of the plugs in said cavity.

6. Spark plug testing and setting apparatus comprising means forming a cavity, a transparent pressure resistant plate secured over said cavity and sealed around the edges thereof, a source of gaseous pressure connected to said cavity, a plurality of threaded holes formed through a wall of said cavity and adapted to receive a plurality of spark plugs, a plurality of gap adjusting rods extending in opposed relation to the bottom points of spark plugs in said holes, means for axially adjusting said rods into gap closing engagement with said points, and a source of high voltage connected on one side to the shells of said plugs and adapted to be connected on the other side to the insulated center terminals of the plugs in said cavity.

7. Spark plug testing and setting apparatus comprising means forming a cavity, a transparent pressure resistant plate secured over said cavity and sealed around the edges thereof, a source of regulatable gaseous pressure connected to said cavity, a plurality of threaded holes formed through a side wall of said member into said cavity and adapted to receive a plurality of spark plugs, adjusting means in said cavity adapted to be arranged in opposed relation to the bottom points of spark plugs in said holes, means for selectively adjusting said adjusting means into gap closing engagement with said points, and a sourceof regulatable high voltage connected on one side to the shellsof said plugs and adapted to be selectively connected on the other side to the insulated center terminals of the plugs in said cavity.

8. Spark plug testing and setting apparatus comprising means forming a cavity, a transparent pressure resistant plate secured over said cavity and sealed around the edges. thereof, a source of gaseous pressure connected to said cavity, a plurality of threaded holes formed through a side wall of said member into said cavity and adapted to receive a plurality of spark plugs, adjusting means in said cavity adapted to be arranged in opposed relation to the bottom points of spark plugs in said holes, means for selectively adjusting said adjusting means into gap closing engagement with said points, and a source of high voltage connected on one side to the shells of said plugs and adapted to be connected on the other side to the insulated center terminals of the plugs in said cavity.

9. Spark plug testing and setting apparatus comprising means for mounting a set of plugs in a cavity having a transparent pressure resistant plate in one side thereof, means for creating a regulatable gaseous pressure in said cavity, means in said cavity and operable from the outside of said cavity for selectively and individually adjustingthe gaps ofsaid spark plugs, and means for applying adjustable high voltage selectively to said plugs.

10. Spark plug testing and setting apparatus comprising means for mounting a set of plugs in a cavity having a transparent pressure resistant plate in one side thereof, means for creating a gaseous pressure in said cavity, means in said cavity and operable from the outside of said cavity for selectively and individually adjusting the gaps of said spark plugs, and means for applying a high voltage to said plugs.

References Cited in the file of this patent UNITED STATES PATENTS 1,497,750 Hopkins June 17, 1924 6 Darnall July 28, 1931 Zeller Dec. 8, 1931 Call Sept. 20, 1949 FOREIGN PATENTS France Sept. 8, 1954 

